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/*
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 * Copyright (c) 2007-2012, Stephen Colebourne & Michael Nascimento Santos
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *  * Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 *
 *  * Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
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 *    may be used to endorse or promote products derived from this software
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 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
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 */
package java.time;

import static java.time.temporal.ChronoField.EPOCH_DAY;
import static java.time.temporal.ChronoField.INSTANT_SECONDS;
import static java.time.temporal.ChronoField.NANO_OF_DAY;
import static java.time.temporal.ChronoField.OFFSET_SECONDS;
import static java.time.temporal.ChronoUnit.FOREVER;
import static java.time.temporal.ChronoUnit.NANOS;

import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectOutput;
import java.io.InvalidObjectException;
import java.io.ObjectInputStream;
import java.io.Serializable;
import java.time.chrono.IsoChronology;
import java.time.format.DateTimeFormatter;
import java.time.format.DateTimeParseException;
import java.time.temporal.ChronoField;
import java.time.temporal.ChronoUnit;
import java.time.temporal.Temporal;
import java.time.temporal.TemporalAccessor;
import java.time.temporal.TemporalAdjuster;
import java.time.temporal.TemporalAmount;
import java.time.temporal.TemporalField;
import java.time.temporal.TemporalQueries;
import java.time.temporal.TemporalQuery;
import java.time.temporal.TemporalUnit;
import java.time.temporal.UnsupportedTemporalTypeException;
import java.time.temporal.ValueRange;
import java.time.zone.ZoneRules;
import java.util.Comparator;
import java.util.Objects;

/**
 * A date-time with an offset from UTC/Greenwich in the ISO-8601 calendar system, such as {@code
 * 2007-12-03T10:15:30+01:00}. <p> {@code OffsetDateTime} is an immutable representation of a
 * date-time with an offset. This class stores all date and time fields, to a precision of
 * nanoseconds, as well as the offset from UTC/Greenwich. For example, the value "2nd October 2007
 * at 13:45.30.123456789 +02:00" can be stored in an {@code OffsetDateTime}. <p> {@code
 * OffsetDateTime}, {@link java.time.ZonedDateTime} and {@link java.time.Instant} all store an
 * instant on the time-line to nanosecond precision. {@code Instant} is the simplest, simply
 * representing the instant. {@code OffsetDateTime} adds to the instant the offset from
 * UTC/Greenwich, which allows the local date-time to be obtained. {@code ZonedDateTime} adds full
 * time-zone rules. <p> It is intended that {@code ZonedDateTime} or {@code Instant} is used to
 * model data in simpler applications. This class may be used when modeling date-time concepts in
 * more detail, or when communicating to a database or in a network protocol.
 *
 * <p> This is a <a href="{@docRoot}/java/lang/doc-files/ValueBased.html">value-based</a> class; use
 * of identity-sensitive operations (including reference equality ({@code ==}), identity hash code,
 * or synchronization) on instances of {@code OffsetDateTime} may have unpredictable results and
 * should be avoided. The {@code equals} method should be used for comparisons.
 *
 * @implSpec This class is immutable and thread-safe.
 * @since 1.8
 */
public final class OffsetDateTime
    implements Temporal, TemporalAdjuster, Comparable<OffsetDateTime>, Serializable {

  /**
   * The minimum supported {@code OffsetDateTime}, '-999999999-01-01T00:00:00+18:00'.
   * This is the local date-time of midnight at the start of the minimum date
   * in the maximum offset (larger offsets are earlier on the time-line).
   * This combines {@link LocalDateTime#MIN} and {@link ZoneOffset#MAX}.
   * This could be used by an application as a "far past" date-time.
   */
  public static final OffsetDateTime MIN = LocalDateTime.MIN.atOffset(ZoneOffset.MAX);
  /**
   * The maximum supported {@code OffsetDateTime}, '+999999999-12-31T23:59:59.999999999-18:00'.
   * This is the local date-time just before midnight at the end of the maximum date
   * in the minimum offset (larger negative offsets are later on the time-line).
   * This combines {@link LocalDateTime#MAX} and {@link ZoneOffset#MIN}.
   * This could be used by an application as a "far future" date-time.
   */
  public static final OffsetDateTime MAX = LocalDateTime.MAX.atOffset(ZoneOffset.MIN);

  /**
   * Gets a comparator that compares two {@code OffsetDateTime} instances
   * based solely on the instant.
   * <p>
   * This method differs from the comparison in {@link #compareTo} in that it
   * only compares the underlying instant.
   *
   * @return a comparator that compares in time-line order
   * @see #isAfter
   * @see #isBefore
   * @see #isEqual
   */
  public static Comparator<OffsetDateTime> timeLineOrder() {
    return OffsetDateTime::compareInstant;
  }

  /**
   * Compares this {@code OffsetDateTime} to another date-time.
   * The comparison is based on the instant.
   *
   * @param datetime1 the first date-time to compare, not null
   * @param datetime2 the other date-time to compare to, not null
   * @return the comparator value, negative if less, positive if greater
   */
  private static int compareInstant(OffsetDateTime datetime1, OffsetDateTime datetime2) {
    if (datetime1.getOffset().equals(datetime2.getOffset())) {
      return datetime1.toLocalDateTime().compareTo(datetime2.toLocalDateTime());
    }
    int cmp = Long.compare(datetime1.toEpochSecond(), datetime2.toEpochSecond());
    if (cmp == 0) {
      cmp = datetime1.toLocalTime().getNano() - datetime2.toLocalTime().getNano();
    }
    return cmp;
  }

  /**
   * Serialization version.
   */
  private static final long serialVersionUID = 2287754244819255394L;

  /**
   * The local date-time.
   */
  private final LocalDateTime dateTime;
  /**
   * The offset from UTC/Greenwich.
   */
  private final ZoneOffset offset;

  //-----------------------------------------------------------------------

  /**
   * Obtains the current date-time from the system clock in the default time-zone.
   * <p>
   * This will query the {@link Clock#systemDefaultZone() system clock} in the default
   * time-zone to obtain the current date-time.
   * The offset will be calculated from the time-zone in the clock.
   * <p>
   * Using this method will prevent the ability to use an alternate clock for testing
   * because the clock is hard-coded.
   *
   * @return the current date-time using the system clock, not null
   */
  public static OffsetDateTime now() {
    return now(Clock.systemDefaultZone());
  }

  /**
   * Obtains the current date-time from the system clock in the specified time-zone.
   * <p>
   * This will query the {@link Clock#system(ZoneId) system clock} to obtain the current date-time.
   * Specifying the time-zone avoids dependence on the default time-zone.
   * The offset will be calculated from the specified time-zone.
   * <p>
   * Using this method will prevent the ability to use an alternate clock for testing
   * because the clock is hard-coded.
   *
   * @param zone the zone ID to use, not null
   * @return the current date-time using the system clock, not null
   */
  public static OffsetDateTime now(ZoneId zone) {
    return now(Clock.system(zone));
  }

  /**
   * Obtains the current date-time from the specified clock.
   * <p>
   * This will query the specified clock to obtain the current date-time.
   * The offset will be calculated from the time-zone in the clock.
   * <p>
   * Using this method allows the use of an alternate clock for testing.
   * The alternate clock may be introduced using {@link Clock dependency injection}.
   *
   * @param clock the clock to use, not null
   * @return the current date-time, not null
   */
  public static OffsetDateTime now(Clock clock) {
    Objects.requireNonNull(clock, "clock");
    final Instant now = clock.instant();  // called once
    return ofInstant(now, clock.getZone().getRules().getOffset(now));
  }

  //-----------------------------------------------------------------------

  /**
   * Obtains an instance of {@code OffsetDateTime} from a date, time and offset.
   * <p>
   * This creates an offset date-time with the specified local date, time and offset.
   *
   * @param date the local date, not null
   * @param time the local time, not null
   * @param offset the zone offset, not null
   * @return the offset date-time, not null
   */
  public static OffsetDateTime of(LocalDate date, LocalTime time, ZoneOffset offset) {
    LocalDateTime dt = LocalDateTime.of(date, time);
    return new OffsetDateTime(dt, offset);
  }

  /**
   * Obtains an instance of {@code OffsetDateTime} from a date-time and offset.
   * <p>
   * This creates an offset date-time with the specified local date-time and offset.
   *
   * @param dateTime the local date-time, not null
   * @param offset the zone offset, not null
   * @return the offset date-time, not null
   */
  public static OffsetDateTime of(LocalDateTime dateTime, ZoneOffset offset) {
    return new OffsetDateTime(dateTime, offset);
  }

  /**
   * Obtains an instance of {@code OffsetDateTime} from a year, month, day,
   * hour, minute, second, nanosecond and offset.
   * <p>
   * This creates an offset date-time with the seven specified fields.
   * <p>
   * This method exists primarily for writing test cases.
   * Non test-code will typically use other methods to create an offset time.
   * {@code LocalDateTime} has five additional convenience variants of the
   * equivalent factory method taking fewer arguments.
   * They are not provided here to reduce the footprint of the API.
   *
   * @param year the year to represent, from MIN_YEAR to MAX_YEAR
   * @param month the month-of-year to represent, from 1 (January) to 12 (December)
   * @param dayOfMonth the day-of-month to represent, from 1 to 31
   * @param hour the hour-of-day to represent, from 0 to 23
   * @param minute the minute-of-hour to represent, from 0 to 59
   * @param second the second-of-minute to represent, from 0 to 59
   * @param nanoOfSecond the nano-of-second to represent, from 0 to 999,999,999
   * @param offset the zone offset, not null
   * @return the offset date-time, not null
   * @throws DateTimeException if the value of any field is out of range, or if the day-of-month is
   * invalid for the month-year
   */
  public static OffsetDateTime of(
      int year, int month, int dayOfMonth,
      int hour, int minute, int second, int nanoOfSecond, ZoneOffset offset) {
    LocalDateTime dt = LocalDateTime
        .of(year, month, dayOfMonth, hour, minute, second, nanoOfSecond);
    return new OffsetDateTime(dt, offset);
  }

  //-----------------------------------------------------------------------

  /**
   * Obtains an instance of {@code OffsetDateTime} from an {@code Instant} and zone ID.
   * <p>
   * This creates an offset date-time with the same instant as that specified.
   * Finding the offset from UTC/Greenwich is simple as there is only one valid
   * offset for each instant.
   *
   * @param instant the instant to create the date-time from, not null
   * @param zone the time-zone, which may be an offset, not null
   * @return the offset date-time, not null
   * @throws DateTimeException if the result exceeds the supported range
   */
  public static OffsetDateTime ofInstant(Instant instant, ZoneId zone) {
    Objects.requireNonNull(instant, "instant");
    Objects.requireNonNull(zone, "zone");
    ZoneRules rules = zone.getRules();
    ZoneOffset offset = rules.getOffset(instant);
    LocalDateTime ldt = LocalDateTime
        .ofEpochSecond(instant.getEpochSecond(), instant.getNano(), offset);
    return new OffsetDateTime(ldt, offset);
  }

  //-----------------------------------------------------------------------

  /**
   * Obtains an instance of {@code OffsetDateTime} from a temporal object. <p> This obtains an
   * offset date-time based on the specified temporal. A {@code TemporalAccessor} represents an
   * arbitrary set of date and time information, which this factory converts to an instance of
   * {@code OffsetDateTime}. <p> The conversion will first obtain a {@code ZoneOffset} from the
   * temporal object. It will then try to obtain a {@code LocalDateTime}, falling back to an {@code
   * Instant} if necessary. The result will be the combination of {@code ZoneOffset} with either
   * with {@code LocalDateTime} or {@code Instant}. Implementations are permitted to perform
   * optimizations such as accessing those fields that are equivalent to the relevant objects. <p>
   * This method matches the signature of the functional interface {@link TemporalQuery} allowing it
   * to be used as a query via method reference, {@code OffsetDateTime::from}.
   *
   * @param temporal the temporal object to convert, not null
   * @return the offset date-time, not null
   * @throws DateTimeException if unable to convert to an {@code OffsetDateTime}
   */
  public static OffsetDateTime from(TemporalAccessor temporal) {
    if (temporal instanceof OffsetDateTime) {
      return (OffsetDateTime) temporal;
    }
    try {
      ZoneOffset offset = ZoneOffset.from(temporal);
      LocalDate date = temporal.query(TemporalQueries.localDate());
      LocalTime time = temporal.query(TemporalQueries.localTime());
      if (date != null && time != null) {
        return OffsetDateTime.of(date, time, offset);
      } else {
        Instant instant = Instant.from(temporal);
        return OffsetDateTime.ofInstant(instant, offset);
      }
    } catch (DateTimeException ex) {
      throw new DateTimeException("Unable to obtain OffsetDateTime from TemporalAccessor: " +
          temporal + " of type " + temporal.getClass().getName(), ex);
    }
  }

  //-----------------------------------------------------------------------

  /**
   * Obtains an instance of {@code OffsetDateTime} from a text string
   * such as {@code 2007-12-03T10:15:30+01:00}.
   * <p>
   * The string must represent a valid date-time and is parsed using
   * {@link java.time.format.DateTimeFormatter#ISO_OFFSET_DATE_TIME}.
   *
   * @param text the text to parse such as "2007-12-03T10:15:30+01:00", not null
   * @return the parsed offset date-time, not null
   * @throws DateTimeParseException if the text cannot be parsed
   */
  public static OffsetDateTime parse(CharSequence text) {
    return parse(text, DateTimeFormatter.ISO_OFFSET_DATE_TIME);
  }

  /**
   * Obtains an instance of {@code OffsetDateTime} from a text string using a specific formatter.
   * <p>
   * The text is parsed using the formatter, returning a date-time.
   *
   * @param text the text to parse, not null
   * @param formatter the formatter to use, not null
   * @return the parsed offset date-time, not null
   * @throws DateTimeParseException if the text cannot be parsed
   */
  public static OffsetDateTime parse(CharSequence text, DateTimeFormatter formatter) {
    Objects.requireNonNull(formatter, "formatter");
    return formatter.parse(text, OffsetDateTime::from);
  }

  //-----------------------------------------------------------------------

  /**
   * Constructor.
   *
   * @param dateTime the local date-time, not null
   * @param offset the zone offset, not null
   */
  private OffsetDateTime(LocalDateTime dateTime, ZoneOffset offset) {
    this.dateTime = Objects.requireNonNull(dateTime, "dateTime");
    this.offset = Objects.requireNonNull(offset, "offset");
  }

  /**
   * Returns a new date-time based on this one, returning {@code this} where possible.
   *
   * @param dateTime the date-time to create with, not null
   * @param offset the zone offset to create with, not null
   */
  private OffsetDateTime with(LocalDateTime dateTime, ZoneOffset offset) {
    if (this.dateTime == dateTime && this.offset.equals(offset)) {
      return this;
    }
    return new OffsetDateTime(dateTime, offset);
  }

  //-----------------------------------------------------------------------

  /**
   * Checks if the specified field is supported.
   * <p>
   * This checks if this date-time can be queried for the specified field.
   * If false, then calling the {@link #range(TemporalField) range},
   * {@link #get(TemporalField) get} and {@link #with(TemporalField, long)}
   * methods will throw an exception.
   * <p>
   * If the field is a {@link ChronoField} then the query is implemented here.
   * The supported fields are:
   * <ul>
   * <li>{@code NANO_OF_SECOND}
   * <li>{@code NANO_OF_DAY}
   * <li>{@code MICRO_OF_SECOND}
   * <li>{@code MICRO_OF_DAY}
   * <li>{@code MILLI_OF_SECOND}
   * <li>{@code MILLI_OF_DAY}
   * <li>{@code SECOND_OF_MINUTE}
   * <li>{@code SECOND_OF_DAY}
   * <li>{@code MINUTE_OF_HOUR}
   * <li>{@code MINUTE_OF_DAY}
   * <li>{@code HOUR_OF_AMPM}
   * <li>{@code CLOCK_HOUR_OF_AMPM}
   * <li>{@code HOUR_OF_DAY}
   * <li>{@code CLOCK_HOUR_OF_DAY}
   * <li>{@code AMPM_OF_DAY}
   * <li>{@code DAY_OF_WEEK}
   * <li>{@code ALIGNED_DAY_OF_WEEK_IN_MONTH}
   * <li>{@code ALIGNED_DAY_OF_WEEK_IN_YEAR}
   * <li>{@code DAY_OF_MONTH}
   * <li>{@code DAY_OF_YEAR}
   * <li>{@code EPOCH_DAY}
   * <li>{@code ALIGNED_WEEK_OF_MONTH}
   * <li>{@code ALIGNED_WEEK_OF_YEAR}
   * <li>{@code MONTH_OF_YEAR}
   * <li>{@code PROLEPTIC_MONTH}
   * <li>{@code YEAR_OF_ERA}
   * <li>{@code YEAR}
   * <li>{@code ERA}
   * <li>{@code INSTANT_SECONDS}
   * <li>{@code OFFSET_SECONDS}
   * </ul>
   * All other {@code ChronoField} instances will return false.
   * <p>
   * If the field is not a {@code ChronoField}, then the result of this method
   * is obtained by invoking {@code TemporalField.isSupportedBy(TemporalAccessor)}
   * passing {@code this} as the argument.
   * Whether the field is supported is determined by the field.
   *
   * @param field the field to check, null returns false
   * @return true if the field is supported on this date-time, false if not
   */
  @Override
  public boolean isSupported(TemporalField field) {
    return field instanceof ChronoField || (field != null && field.isSupportedBy(this));
  }

  /**
   * Checks if the specified unit is supported.
   * <p>
   * This checks if the specified unit can be added to, or subtracted from, this date-time.
   * If false, then calling the {@link #plus(long, TemporalUnit)} and
   * {@link #minus(long, TemporalUnit) minus} methods will throw an exception.
   * <p>
   * If the unit is a {@link ChronoUnit} then the query is implemented here.
   * The supported units are:
   * <ul>
   * <li>{@code NANOS}
   * <li>{@code MICROS}
   * <li>{@code MILLIS}
   * <li>{@code SECONDS}
   * <li>{@code MINUTES}
   * <li>{@code HOURS}
   * <li>{@code HALF_DAYS}
   * <li>{@code DAYS}
   * <li>{@code WEEKS}
   * <li>{@code MONTHS}
   * <li>{@code YEARS}
   * <li>{@code DECADES}
   * <li>{@code CENTURIES}
   * <li>{@code MILLENNIA}
   * <li>{@code ERAS}
   * </ul>
   * All other {@code ChronoUnit} instances will return false.
   * <p>
   * If the unit is not a {@code ChronoUnit}, then the result of this method
   * is obtained by invoking {@code TemporalUnit.isSupportedBy(Temporal)}
   * passing {@code this} as the argument.
   * Whether the unit is supported is determined by the unit.
   *
   * @param unit the unit to check, null returns false
   * @return true if the unit can be added/subtracted, false if not
   */
  @Override  // override for Javadoc
  public boolean isSupported(TemporalUnit unit) {
    if (unit instanceof ChronoUnit) {
      return unit != FOREVER;
    }
    return unit != null && unit.isSupportedBy(this);
  }

  //-----------------------------------------------------------------------

  /**
   * Gets the range of valid values for the specified field.
   * <p>
   * The range object expresses the minimum and maximum valid values for a field.
   * This date-time is used to enhance the accuracy of the returned range.
   * If it is not possible to return the range, because the field is not supported
   * or for some other reason, an exception is thrown.
   * <p>
   * If the field is a {@link ChronoField} then the query is implemented here.
   * The {@link #isSupported(TemporalField) supported fields} will return
   * appropriate range instances.
   * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}.
   * <p>
   * If the field is not a {@code ChronoField}, then the result of this method
   * is obtained by invoking {@code TemporalField.rangeRefinedBy(TemporalAccessor)}
   * passing {@code this} as the argument.
   * Whether the range can be obtained is determined by the field.
   *
   * @param field the field to query the range for, not null
   * @return the range of valid values for the field, not null
   * @throws DateTimeException if the range for the field cannot be obtained
   * @throws UnsupportedTemporalTypeException if the field is not supported
   */
  @Override
  public ValueRange range(TemporalField field) {
    if (field instanceof ChronoField) {
      if (field == INSTANT_SECONDS || field == OFFSET_SECONDS) {
        return field.range();
      }
      return dateTime.range(field);
    }
    return field.rangeRefinedBy(this);
  }

  /**
   * Gets the value of the specified field from this date-time as an {@code int}.
   * <p>
   * This queries this date-time for the value of the specified field.
   * The returned value will always be within the valid range of values for the field.
   * If it is not possible to return the value, because the field is not supported
   * or for some other reason, an exception is thrown.
   * <p>
   * If the field is a {@link ChronoField} then the query is implemented here.
   * The {@link #isSupported(TemporalField) supported fields} will return valid
   * values based on this date-time, except {@code NANO_OF_DAY}, {@code MICRO_OF_DAY},
   * {@code EPOCH_DAY}, {@code PROLEPTIC_MONTH} and {@code INSTANT_SECONDS} which are too
   * large to fit in an {@code int} and throw a {@code DateTimeException}.
   * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}.
   * <p>
   * If the field is not a {@code ChronoField}, then the result of this method
   * is obtained by invoking {@code TemporalField.getFrom(TemporalAccessor)}
   * passing {@code this} as the argument. Whether the value can be obtained,
   * and what the value represents, is determined by the field.
   *
   * @param field the field to get, not null
   * @return the value for the field
   * @throws DateTimeException if a value for the field cannot be obtained or the value is outside
   * the range of valid values for the field
   * @throws UnsupportedTemporalTypeException if the field is not supported or the range of values
   * exceeds an {@code int}
   * @throws ArithmeticException if numeric overflow occurs
   */
  @Override
  public int get(TemporalField field) {
    if (field instanceof ChronoField) {
      switch ((ChronoField) field) {
        case INSTANT_SECONDS:
          throw new UnsupportedTemporalTypeException(
              "Invalid field 'InstantSeconds' for get() method, use getLong() instead");
        case OFFSET_SECONDS:
          return getOffset().getTotalSeconds();
      }
      return dateTime.get(field);
    }
    return Temporal.super.get(field);
  }

  /**
   * Gets the value of the specified field from this date-time as a {@code long}.
   * <p>
   * This queries this date-time for the value of the specified field.
   * If it is not possible to return the value, because the field is not supported
   * or for some other reason, an exception is thrown.
   * <p>
   * If the field is a {@link ChronoField} then the query is implemented here.
   * The {@link #isSupported(TemporalField) supported fields} will return valid
   * values based on this date-time.
   * All other {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}.
   * <p>
   * If the field is not a {@code ChronoField}, then the result of this method
   * is obtained by invoking {@code TemporalField.getFrom(TemporalAccessor)}
   * passing {@code this} as the argument. Whether the value can be obtained,
   * and what the value represents, is determined by the field.
   *
   * @param field the field to get, not null
   * @return the value for the field
   * @throws DateTimeException if a value for the field cannot be obtained
   * @throws UnsupportedTemporalTypeException if the field is not supported
   * @throws ArithmeticException if numeric overflow occurs
   */
  @Override
  public long getLong(TemporalField field) {
    if (field instanceof ChronoField) {
      switch ((ChronoField) field) {
        case INSTANT_SECONDS:
          return toEpochSecond();
        case OFFSET_SECONDS:
          return getOffset().getTotalSeconds();
      }
      return dateTime.getLong(field);
    }
    return field.getFrom(this);
  }

  //-----------------------------------------------------------------------

  /**
   * Gets the zone offset, such as '+01:00'.
   * <p>
   * This is the offset of the local date-time from UTC/Greenwich.
   *
   * @return the zone offset, not null
   */
  public ZoneOffset getOffset() {
    return offset;
  }

  /**
   * Returns a copy of this {@code OffsetDateTime} with the specified offset ensuring that the
   * result has the same local date-time. <p> This method returns an object with the same {@code
   * LocalDateTime} and the specified {@code ZoneOffset}. No calculation is needed or performed. For
   * example, if this time represents {@code 2007-12-03T10:30+02:00} and the offset specified is
   * {@code +03:00}, then this method will return {@code 2007-12-03T10:30+03:00}. <p> To take into
   * account the difference between the offsets, and adjust the time fields, use {@link
   * #withOffsetSameInstant}. <p> This instance is immutable and unaffected by this method call.
   *
   * @param offset the zone offset to change to, not null
   * @return an {@code OffsetDateTime} based on this date-time with the requested offset, not null
   */
  public OffsetDateTime withOffsetSameLocal(ZoneOffset offset) {
    return with(dateTime, offset);
  }

  /**
   * Returns a copy of this {@code OffsetDateTime} with the specified offset ensuring
   * that the result is at the same instant.
   * <p>
   * This method returns an object with the specified {@code ZoneOffset} and a {@code LocalDateTime}
   * adjusted by the difference between the two offsets.
   * This will result in the old and new objects representing the same instant.
   * This is useful for finding the local time in a different offset.
   * For example, if this time represents {@code 2007-12-03T10:30+02:00} and the offset specified is
   * {@code +03:00}, then this method will return {@code 2007-12-03T11:30+03:00}.
   * <p>
   * To change the offset without adjusting the local time use {@link #withOffsetSameLocal}.
   * <p>
   * This instance is immutable and unaffected by this method call.
   *
   * @param offset the zone offset to change to, not null
   * @return an {@code OffsetDateTime} based on this date-time with the requested offset, not null
   * @throws DateTimeException if the result exceeds the supported date range
   */
  public OffsetDateTime withOffsetSameInstant(ZoneOffset offset) {
    if (offset.equals(this.offset)) {
      return this;
    }
    int difference = offset.getTotalSeconds() - this.offset.getTotalSeconds();
    LocalDateTime adjusted = dateTime.plusSeconds(difference);
    return new OffsetDateTime(adjusted, offset);
  }

  //-----------------------------------------------------------------------

  /**
   * Gets the {@code LocalDateTime} part of this date-time.
   * <p>
   * This returns a {@code LocalDateTime} with the same year, month, day and time
   * as this date-time.
   *
   * @return the local date-time part of this date-time, not null
   */
  public LocalDateTime toLocalDateTime() {
    return dateTime;
  }

  //-----------------------------------------------------------------------

  /**
   * Gets the {@code LocalDate} part of this date-time.
   * <p>
   * This returns a {@code LocalDate} with the same year, month and day
   * as this date-time.
   *
   * @return the date part of this date-time, not null
   */
  public LocalDate toLocalDate() {
    return dateTime.toLocalDate();
  }

  /**
   * Gets the year field.
   * <p>
   * This method returns the primitive {@code int} value for the year.
   * <p>
   * The year returned by this method is proleptic as per {@code get(YEAR)}.
   * To obtain the year-of-era, use {@code get(YEAR_OF_ERA)}.
   *
   * @return the year, from MIN_YEAR to MAX_YEAR
   */
  public int getYear() {
    return dateTime.getYear();
  }

  /**
   * Gets the month-of-year field from 1 to 12.
   * <p>
   * This method returns the month as an {@code int} from 1 to 12.
   * Application code is frequently clearer if the enum {@link Month}
   * is used by calling {@link #getMonth()}.
   *
   * @return the month-of-year, from 1 to 12
   * @see #getMonth()
   */
  public int getMonthValue() {
    return dateTime.getMonthValue();
  }

  /**
   * Gets the month-of-year field using the {@code Month} enum.
   * <p>
   * This method returns the enum {@link Month} for the month.
   * This avoids confusion as to what {@code int} values mean.
   * If you need access to the primitive {@code int} value then the enum
   * provides the {@link Month#getValue() int value}.
   *
   * @return the month-of-year, not null
   * @see #getMonthValue()
   */
  public Month getMonth() {
    return dateTime.getMonth();
  }

  /**
   * Gets the day-of-month field.
   * <p>
   * This method returns the primitive {@code int} value for the day-of-month.
   *
   * @return the day-of-month, from 1 to 31
   */
  public int getDayOfMonth() {
    return dateTime.getDayOfMonth();
  }

  /**
   * Gets the day-of-year field.
   * <p>
   * This method returns the primitive {@code int} value for the day-of-year.
   *
   * @return the day-of-year, from 1 to 365, or 366 in a leap year
   */
  public int getDayOfYear() {
    return dateTime.getDayOfYear();
  }

  /**
   * Gets the day-of-week field, which is an enum {@code DayOfWeek}.
   * <p>
   * This method returns the enum {@link DayOfWeek} for the day-of-week.
   * This avoids confusion as to what {@code int} values mean.
   * If you need access to the primitive {@code int} value then the enum
   * provides the {@link DayOfWeek#getValue() int value}.
   * <p>
   * Additional information can be obtained from the {@code DayOfWeek}.
   * This includes textual names of the values.
   *
   * @return the day-of-week, not null
   */
  public DayOfWeek getDayOfWeek() {
    return dateTime.getDayOfWeek();
  }

  //-----------------------------------------------------------------------

  /**
   * Gets the {@code LocalTime} part of this date-time.
   * <p>
   * This returns a {@code LocalTime} with the same hour, minute, second and
   * nanosecond as this date-time.
   *
   * @return the time part of this date-time, not null
   */
  public LocalTime toLocalTime() {
    return dateTime.toLocalTime();
  }

  /**
   * Gets the hour-of-day field.
   *
   * @return the hour-of-day, from 0 to 23
   */
  public int getHour() {
    return dateTime.getHour();
  }

  /**
   * Gets the minute-of-hour field.
   *
   * @return the minute-of-hour, from 0 to 59
   */
  public int getMinute() {
    return dateTime.getMinute();
  }

  /**
   * Gets the second-of-minute field.
   *
   * @return the second-of-minute, from 0 to 59
   */
  public int getSecond() {
    return dateTime.getSecond();
  }

  /**
   * Gets the nano-of-second field.
   *
   * @return the nano-of-second, from 0 to 999,999,999
   */
  public int getNano() {
    return dateTime.getNano();
  }

  //-----------------------------------------------------------------------

  /**
   * Returns an adjusted copy of this date-time.
   * <p>
   * This returns an {@code OffsetDateTime}, based on this one, with the date-time adjusted.
   * The adjustment takes place using the specified adjuster strategy object.
   * Read the documentation of the adjuster to understand what adjustment will be made.
   * <p>
   * A simple adjuster might simply set the one of the fields, such as the year field.
   * A more complex adjuster might set the date to the last day of the month.
   * A selection of common adjustments is provided in
   * {@link java.time.temporal.TemporalAdjusters TemporalAdjusters}.
   * These include finding the "last day of the month" and "next Wednesday".
   * Key date-time classes also implement the {@code TemporalAdjuster} interface,
   * such as {@link Month} and {@link java.time.MonthDay MonthDay}.
   * The adjuster is responsible for handling special cases, such as the varying
   * lengths of month and leap years.
   * <p>
   * For example this code returns a date on the last day of July:
   * <pre>
   *  import static java.time.Month.*;
   *  import static java.time.temporal.TemporalAdjusters.*;
   *
   *  result = offsetDateTime.with(JULY).with(lastDayOfMonth());
   * </pre>
   * <p>
   * The classes {@link LocalDate}, {@link LocalTime} and {@link ZoneOffset} implement
   * {@code TemporalAdjuster}, thus this method can be used to change the date, time or offset:
   * <pre>
   *  result = offsetDateTime.with(date);
   *  result = offsetDateTime.with(time);
   *  result = offsetDateTime.with(offset);
   * </pre>
   * <p>
   * The result of this method is obtained by invoking the
   * {@link TemporalAdjuster#adjustInto(Temporal)} method on the
   * specified adjuster passing {@code this} as the argument.
   * <p>
   * This instance is immutable and unaffected by this method call.
   *
   * @param adjuster the adjuster to use, not null
   * @return an {@code OffsetDateTime} based on {@code this} with the adjustment made, not null
   * @throws DateTimeException if the adjustment cannot be made
   * @throws ArithmeticException if numeric overflow occurs
   */
  @Override
  public OffsetDateTime with(TemporalAdjuster adjuster) {
    // optimizations
    if (adjuster instanceof LocalDate || adjuster instanceof LocalTime
        || adjuster instanceof LocalDateTime) {
      return with(dateTime.with(adjuster), offset);
    } else if (adjuster instanceof Instant) {
      return ofInstant((Instant) adjuster, offset);
    } else if (adjuster instanceof ZoneOffset) {
      return with(dateTime, (ZoneOffset) adjuster);
    } else if (adjuster instanceof OffsetDateTime) {
      return (OffsetDateTime) adjuster;
    }
    return (OffsetDateTime) adjuster.adjustInto(this);
  }

  /**
   * Returns a copy of this date-time with the specified field set to a new value. <p> This returns
   * an {@code OffsetDateTime}, based on this one, with the value for the specified field changed.
   * This can be used to change any supported field, such as the year, month or day-of-month. If it
   * is not possible to set the value, because the field is not supported or for some other reason,
   * an exception is thrown. <p> In some cases, changing the specified field can cause the resulting
   * date-time to become invalid, such as changing the month from 31st January to February would
   * make the day-of-month invalid. In cases like this, the field is responsible for resolving the
   * date. Typically it will choose the previous valid date, which would be the last valid day of
   * February in this example. <p> If the field is a {@link ChronoField} then the adjustment is
   * implemented here. <p> The {@code INSTANT_SECONDS} field will return a date-time with the
   * specified instant. The offset and nano-of-second are unchanged. If the new instant value is
   * outside the valid range then a {@code DateTimeException} will be thrown. <p> The {@code
   * OFFSET_SECONDS} field will return a date-time with the specified offset. The local date-time is
   * unaltered. If the new offset value is outside the valid range then a {@code DateTimeException}
   * will be thrown. <p> The other {@link #isSupported(TemporalField) supported fields} will behave
   * as per the matching method on {@link LocalDateTime#with(TemporalField, long) LocalDateTime}. In
   * this case, the offset is not part of the calculation and will be unchanged. <p> All other
   * {@code ChronoField} instances will throw an {@code UnsupportedTemporalTypeException}. <p> If
   * the field is not a {@code ChronoField}, then the result of this method is obtained by invoking
   * {@code TemporalField.adjustInto(Temporal, long)} passing {@code this} as the argument. In this
   * case, the field determines whether and how to adjust the instant. <p> This instance is
   * immutable and unaffected by this method call.
   *
   * @param field the field to set in the result, not null
   * @param newValue the new value of the field in the result
   * @return an {@code OffsetDateTime} based on {@code this} with the specified field set, not null
   * @throws DateTimeException if the field cannot be set
   * @throws UnsupportedTemporalTypeException if the field is not supported
   * @throws ArithmeticException if numeric overflow occurs
   */
  @Override
  public OffsetDateTime with(TemporalField field, long newValue) {
    if (field instanceof ChronoField) {
      ChronoField f = (ChronoField) field;
      switch (f) {
        case INSTANT_SECONDS:
          return ofInstant(Instant.ofEpochSecond(newValue, getNano()), offset);
        case OFFSET_SECONDS: {
          return with(dateTime, ZoneOffset.ofTotalSeconds(f.checkValidIntValue(newValue)));
        }
      }
      return with(dateTime.with(field, newValue), offset);
    }
    return field.adjustInto(this, newValue);
  }

  //-----------------------------------------------------------------------

  /**
   * Returns a copy of this {@code OffsetDateTime} with the year altered. <p> The time and offset do
   * not affect the calculation and will be the same in the result. If the day-of-month is invalid
   * for the year, it will be changed to the last valid day of the month. <p> This instance is
   * immutable and unaffected by this method call.
   *
   * @param year the year to set in the result, from MIN_YEAR to MAX_YEAR
   * @return an {@code OffsetDateTime} based on this date-time with the requested year, not null
   * @throws DateTimeException if the year value is invalid
   */
  public OffsetDateTime withYear(int year) {
    return with(dateTime.withYear(year), offset);
  }

  /**
   * Returns a copy of this {@code OffsetDateTime} with the month-of-year altered. <p> The time and
   * offset do not affect the calculation and will be the same in the result. If the day-of-month is
   * invalid for the year, it will be changed to the last valid day of the month. <p> This instance
   * is immutable and unaffected by this method call.
   *
   * @param month the month-of-year to set in the result, from 1 (January) to 12 (December)
   * @return an {@code OffsetDateTime} based on this date-time with the requested month, not null
   * @throws DateTimeException if the month-of-year value is invalid
   */
  public OffsetDateTime withMonth(int month) {
    return with(dateTime.withMonth(month), offset);
  }

  /**
   * Returns a copy of this {@code OffsetDateTime} with the day-of-month altered.
   * <p>
   * If the resulting {@code OffsetDateTime} is invalid, an exception is thrown.
   * The time and offset do not affect the calculation and will be the same in the result.
   * <p>
   * This instance is immutable and unaffected by this method call.
   *
   * @param dayOfMonth the day-of-month to set in the result, from 1 to 28-31
   * @return an {@code OffsetDateTime} based on this date-time with the requested day, not null
   * @throws DateTimeException if the day-of-month value is invalid, or if the day-of-month is
   * invalid for the month-year
   */
  public OffsetDateTime withDayOfMonth(int dayOfMonth) {
    return with(dateTime.withDayOfMonth(dayOfMonth), offset);
  }

  /**
   * Returns a copy of this {@code OffsetDateTime} with the day-of-year altered.
   * <p>
   * The time and offset do not affect the calculation and will be the same in the result.
   * If the resulting {@code OffsetDateTime} is invalid, an exception is thrown.
   * <p>
   * This instance is immutable and unaffected by this method call.
   *
   * @param dayOfYear the day-of-year to set in the result, from 1 to 365-366
   * @return an {@code OffsetDateTime} based on this date with the requested day, not null
   * @throws DateTimeException if the day-of-year value is invalid, or if the day-of-year is invalid
   * for the year
   */
  public OffsetDateTime withDayOfYear(int dayOfYear) {
    return with(dateTime.withDayOfYear(dayOfYear), offset);
  }

  //-----------------------------------------------------------------------

  /**
   * Returns a copy of this {@code OffsetDateTime} with the hour-of-day altered.
   * <p>
   * The date and offset do not affect the calculation and will be the same in the result.
   * <p>
   * This instance is immutable and unaffected by this method call.
   *
   * @param hour the hour-of-day to set in the result, from 0 to 23
   * @return an {@code OffsetDateTime} based on this date-time with the requested hour, not null
   * @throws DateTimeException if the hour value is invalid
   */
  public OffsetDateTime withHour(int hour) {
    return with(dateTime.withHour(hour), offset);
  }

  /**
   * Returns a copy of this {@code OffsetDateTime} with the minute-of-hour altered.
   * <p>
   * The date and offset do not affect the calculation and will be the same in the result.
   * <p>
   * This instance is immutable and unaffected by this method call.
   *
   * @param minute the minute-of-hour to set in the result, from 0 to 59
   * @return an {@code OffsetDateTime} based on this date-time with the requested minute, not null
   * @throws DateTimeException if the minute value is invalid
   */
  public OffsetDateTime withMinute(int minute) {
    return with(dateTime.withMinute(minute), offset);
  }

  /**
   * Returns a copy of this {@code OffsetDateTime} with the second-of-minute altered.
   * <p>
   * The date and offset do not affect the calculation and will be the same in the result.
   * <p>
   * This instance is immutable and unaffected by this method call.
   *
   * @param second the second-of-minute to set in the result, from 0 to 59
   * @return an {@code OffsetDateTime} based on this date-time with the requested second, not null
   * @throws DateTimeException if the second value is invalid
   */
  public OffsetDateTime withSecond(int second) {
    return with(dateTime.withSecond(second), offset);
  }

  /**
   * Returns a copy of this {@code OffsetDateTime} with the nano-of-second altered.
   * <p>
   * The date and offset do not affect the calculation and will be the same in the result.
   * <p>
   * This instance is immutable and unaffected by this method call.
   *
   * @param nanoOfSecond the nano-of-second to set in the result, from 0 to 999,999,999
   * @return an {@code OffsetDateTime} based on this date-time with the requested nanosecond, not
   * null
   * @throws DateTimeException if the nano value is invalid
   */
  public OffsetDateTime withNano(int nanoOfSecond) {
    return with(dateTime.withNano(nanoOfSecond), offset);
  }

  //-----------------------------------------------------------------------

  /**
   * Returns a copy of this {@code OffsetDateTime} with the time truncated.
   * <p>
   * Truncation returns a copy of the original date-time with fields
   * smaller than the specified unit set to zero.
   * For example, truncating with the {@link ChronoUnit#MINUTES minutes} unit
   * will set the second-of-minute and nano-of-second field to zero.
   * <p>
   * The unit must have a {@linkplain TemporalUnit#getDuration() duration}
   * that divides into the length of a standard day without remainder.
   * This includes all supplied time units on {@link ChronoUnit} and
   * {@link ChronoUnit#DAYS DAYS}. Other units throw an exception.
   * <p>
   * The offset does not affect the calculation and will be the same in the result.
   * <p>
   * This instance is immutable and unaffected by this method call.
   *
   * @param unit the unit to truncate to, not null
   * @return an {@code OffsetDateTime} based on this date-time with the time truncated, not null
   * @throws DateTimeException if unable to truncate
   * @throws UnsupportedTemporalTypeException if the unit is not supported
   */
  public OffsetDateTime truncatedTo(TemporalUnit unit) {
    return with(dateTime.truncatedTo(unit), offset);
  }

  //-----------------------------------------------------------------------

  /**
   * Returns a copy of this date-time with the specified amount added.
   * <p>
   * This returns an {@code OffsetDateTime}, based on this one, with the specified amount added.
   * The amount is typically {@link Period} or {@link Duration} but may be
   * any other type implementing the {@link TemporalAmount} interface.
   * <p>
   * The calculation is delegated to the amount object by calling
   * {@link TemporalAmount#addTo(Temporal)}. The amount implementation is free
   * to implement the addition in any way it wishes, however it typically
   * calls back to {@link #plus(long, TemporalUnit)}. Consult the documentation
   * of the amount implementation to determine if it can be successfully added.
   * <p>
   * This instance is immutable and unaffected by this method call.
   *
   * @param amountToAdd the amount to add, not null
   * @return an {@code OffsetDateTime} based on this date-time with the addition made, not null
   * @throws DateTimeException if the addition cannot be made
   * @throws ArithmeticException if numeric overflow occurs
   */
  @Override
  public OffsetDateTime plus(TemporalAmount amountToAdd) {
    return (OffsetDateTime) amountToAdd.addTo(this);
  }

  /**
   * Returns a copy of this date-time with the specified amount added.
   * <p>
   * This returns an {@code OffsetDateTime}, based on this one, with the amount
   * in terms of the unit added. If it is not possible to add the amount, because the
   * unit is not supported or for some other reason, an exception is thrown.
   * <p>
   * If the field is a {@link ChronoUnit} then the addition is implemented by
   * {@link LocalDateTime#plus(long, TemporalUnit)}.
   * The offset is not part of the calculation and will be unchanged in the result.
   * <p>
   * If the field is not a {@code ChronoUnit}, then the result of this method
   * is obtained by invoking {@code TemporalUnit.addTo(Temporal, long)}
   * passing {@code this} as the argument. In this case, the unit determines
   * whether and how to perform the addition.
   * <p>
   * This instance is immutable and unaffected by this method call.
   *
   * @param amountToAdd the amount of the unit to add to the result, may be negative
   * @param unit the unit of the amount to add, not null
   * @return an {@code OffsetDateTime} based on this date-time with the specified amount added, not
   * null
   * @throws DateTimeException if the addition cannot be made
   * @throws UnsupportedTemporalTypeException if the unit is not supported
   * @throws ArithmeticException if numeric overflow occurs
   */
  @Override
  public OffsetDateTime plus(long amountToAdd, TemporalUnit unit) {
    if (unit instanceof ChronoUnit) {
      return with(dateTime.plus(amountToAdd, unit), offset);
    }
    return unit.addTo(this, amountToAdd);
  }

  //-----------------------------------------------------------------------

  /**
   * Returns a copy of this {@code OffsetDateTime} with the specified number of years added.
   * <p>
   * This method adds the specified amount to the years field in three steps:
   * <ol>
   * <li>Add the input years to the year field</li>
   * <li>Check if the resulting date would be invalid</li>
   * <li>Adjust the day-of-month to the last valid day if necessary</li>
   * </ol>
   * <p>
   * For example, 2008-02-29 (leap year) plus one year would result in the
   * invalid date 2009-02-29 (standard year). Instead of returning an invalid
   * result, the last valid day of the month, 2009-02-28, is selected instead.
   * <p>
   * This instance is immutable and unaffected by this method call.
   *
   * @param years the years to add, may be negative
   * @return an {@code OffsetDateTime} based on this date-time with the years added, not null
   * @throws DateTimeException if the result exceeds the supported date range
   */
  public OffsetDateTime plusYears(long years) {
    return with(dateTime.plusYears(years), offset);
  }

  /**
   * Returns a copy of this {@code OffsetDateTime} with the specified number of months added.
   * <p>
   * This method adds the specified amount to the months field in three steps:
   * <ol>
   * <li>Add the input months to the month-of-year field</li>
   * <li>Check if the resulting date would be invalid</li>
   * <li>Adjust the day-of-month to the last valid day if necessary</li>
   * </ol>
   * <p>
   * For example, 2007-03-31 plus one month would result in the invalid date
   * 2007-04-31. Instead of returning an invalid result, the last valid day
   * of the month, 2007-04-30, is selected instead.
   * <p>
   * This instance is immutable and unaffected by this method call.
   *
   * @param months the months to add, may be negative
   * @return an {@code OffsetDateTime} based on this date-time with the months added, not null
   * @throws DateTimeException if the result exceeds the supported date range
   */
  public OffsetDateTime plusMonths(long months) {
    return with(dateTime.plusMonths(months), offset);
  }

  /**
   * Returns a copy of this OffsetDateTime with the specified number of weeks added.
   * <p>
   * This method adds the specified amount in weeks to the days field incrementing
   * the month and year fields as necessary to ensure the result remains valid.
   * The result is only invalid if the maximum/minimum year is exceeded.
   * <p>
   * For example, 2008-12-31 plus one week would result in 2009-01-07.
   * <p>
   * This instance is immutable and unaffected by this method call.
   *
   * @param weeks the weeks to add, may be negative
   * @return an {@code OffsetDateTime} based on this date-time with the weeks added, not null
   * @throws DateTimeException if the result exceeds the supported date range
   */
  public OffsetDateTime plusWeeks(long weeks) {
    return with(dateTime.plusWeeks(weeks), offset);
  }

  /**
   * Returns a copy of this OffsetDateTime with the specified number of days added.
   * <p>
   * This method adds the specified amount to the days field incrementing the
   * month and year fields as necessary to ensure the result remains valid.
   * The result is only invalid if the maximum/minimum year is exceeded.
   * <p>
   * For example, 2008-12-31 plus one day would result in 2009-01-01.
   * <p>
   * This instance is immutable and unaffected by this method call.
   *
   * @param days the days to add, may be negative
   * @return an {@code OffsetDateTime} based on this date-time with the days added, not null
   * @throws DateTimeException if the result exceeds the supported date range
   */
  public OffsetDateTime plusDays(long days) {
    return with(dateTime.plusDays(days), offset);
  }

  /**
   * Returns a copy of this {@code OffsetDateTime} with the specified number of hours added.
   * <p>
   * This instance is immutable and unaffected by this method call.
   *
   * @param hours the hours to add, may be negative
   * @return an {@code OffsetDateTime} based on this date-time with the hours added, not null
   * @throws DateTimeException if the result exceeds the supported date range
   */
  public OffsetDateTime plusHours(long hours) {
    return with(dateTime.plusHours(hours), offset);
  }

  /**
   * Returns a copy of this {@code OffsetDateTime} with the specified number of minutes added.
   * <p>
   * This instance is immutable and unaffected by this method call.
   *
   * @param minutes the minutes to add, may be negative
   * @return an {@code OffsetDateTime} based on this date-time with the minutes added, not null
   * @throws DateTimeException if the result exceeds the supported date range
   */
  public OffsetDateTime plusMinutes(long minutes) {
    return with(dateTime.plusMinutes(minutes), offset);
  }

  /**
   * Returns a copy of this {@code OffsetDateTime} with the specified number of seconds added.
   * <p>
   * This instance is immutable and unaffected by this method call.
   *
   * @param seconds the seconds to add, may be negative
   * @return an {@code OffsetDateTime} based on this date-time with the seconds added, not null
   * @throws DateTimeException if the result exceeds the supported date range
   */
  public OffsetDateTime plusSeconds(long seconds) {
    return with(dateTime.plusSeconds(seconds), offset);
  }

  /**
   * Returns a copy of this {@code OffsetDateTime} with the specified number of nanoseconds added.
   * <p>
   * This instance is immutable and unaffected by this method call.
   *
   * @param nanos the nanos to add, may be negative
   * @return an {@code OffsetDateTime} based on this date-time with the nanoseconds added, not null
   * @throws DateTimeException if the unit cannot be added to this type
   */
  public OffsetDateTime plusNanos(long nanos) {
    return with(dateTime.plusNanos(nanos), offset);
  }

  //-----------------------------------------------------------------------

  /**
   * Returns a copy of this date-time with the specified amount subtracted. <p> This returns an
   * {@code OffsetDateTime}, based on this one, with the specified amount subtracted. The amount is
   * typically {@link Period} or {@link Duration} but may be any other type implementing the {@link
   * TemporalAmount} interface. <p> The calculation is delegated to the amount object by calling
   * {@link TemporalAmount#subtractFrom(Temporal)}. The amount implementation is free to implement
   * the subtraction in any way it wishes, however it typically calls back to {@link #minus(long,
   * TemporalUnit)}. Consult the documentation of the amount implementation to determine if it can
   * be successfully subtracted. <p> This instance is immutable and unaffected by this method call.
   *
   * @param amountToSubtract the amount to subtract, not null
   * @return an {@code OffsetDateTime} based on this date-time with the subtraction made, not null
   * @throws DateTimeException if the subtraction cannot be made
   * @throws ArithmeticException if numeric overflow occurs
   */
  @Override
  public OffsetDateTime minus(TemporalAmount amountToSubtract) {
    return (OffsetDateTime) amountToSubtract.subtractFrom(this);
  }

  /**
   * Returns a copy of this date-time with the specified amount subtracted.
   * <p>
   * This returns an {@code OffsetDateTime}, based on this one, with the amount
   * in terms of the unit subtracted. If it is not possible to subtract the amount,
   * because the unit is not supported or for some other reason, an exception is thrown.
   * <p>
   * This method is equivalent to {@link #plus(long, TemporalUnit)} with the amount negated.
   * See that method for a full description of how addition, and thus subtraction, works.
   * <p>
   * This instance is immutable and unaffected by this method call.
   *
   * @param amountToSubtract the amount of the unit to subtract from the result, may be negative
   * @param unit the unit of the amount to subtract, not null
   * @return an {@code OffsetDateTime} based on this date-time with the specified amount subtracted,
   * not null
   * @throws DateTimeException if the subtraction cannot be made
   * @throws UnsupportedTemporalTypeException if the unit is not supported
   * @throws ArithmeticException if numeric overflow occurs
   */
  @Override
  public OffsetDateTime minus(long amountToSubtract, TemporalUnit unit) {
    return (amountToSubtract == Long.MIN_VALUE ? plus(Long.MAX_VALUE, unit).plus(1, unit)
        : plus(-amountToSubtract, unit));
  }

  //-----------------------------------------------------------------------

  /**
   * Returns a copy of this {@code OffsetDateTime} with the specified number of years subtracted.
   * <p>
   * This method subtracts the specified amount from the years field in three steps:
   * <ol>
   * <li>Subtract the input years from the year field</li>
   * <li>Check if the resulting date would be invalid</li>
   * <li>Adjust the day-of-month to the last valid day if necessary</li>
   * </ol>
   * <p>
   * For example, 2008-02-29 (leap year) minus one year would result in the
   * invalid date 2009-02-29 (standard year). Instead of returning an invalid
   * result, the last valid day of the month, 2009-02-28, is selected instead.
   * <p>
   * This instance is immutable and unaffected by this method call.
   *
   * @param years the years to subtract, may be negative
   * @return an {@code OffsetDateTime} based on this date-time with the years subtracted, not null
   * @throws DateTimeException if the result exceeds the supported date range
   */
  public OffsetDateTime minusYears(long years) {
    return (years == Long.MIN_VALUE ? plusYears(Long.MAX_VALUE).plusYears(1) : plusYears(-years));
  }

  /**
   * Returns a copy of this {@code OffsetDateTime} with the specified number of months subtracted.
   * <p>
   * This method subtracts the specified amount from the months field in three steps:
   * <ol>
   * <li>Subtract the input months from the month-of-year field</li>
   * <li>Check if the resulting date would be invalid</li>
   * <li>Adjust the day-of-month to the last valid day if necessary</li>
   * </ol>
   * <p>
   * For example, 2007-03-31 minus one month would result in the invalid date
   * 2007-04-31. Instead of returning an invalid result, the last valid day
   * of the month, 2007-04-30, is selected instead.
   * <p>
   * This instance is immutable and unaffected by this method call.
   *
   * @param months the months to subtract, may be negative
   * @return an {@code OffsetDateTime} based on this date-time with the months subtracted, not null
   * @throws DateTimeException if the result exceeds the supported date range
   */
  public OffsetDateTime minusMonths(long months) {
    return (months == Long.MIN_VALUE ? plusMonths(Long.MAX_VALUE).plusMonths(1)
        : plusMonths(-months));
  }

  /**
   * Returns a copy of this {@code OffsetDateTime} with the specified number of weeks subtracted.
   * <p>
   * This method subtracts the specified amount in weeks from the days field decrementing
   * the month and year fields as necessary to ensure the result remains valid.
   * The result is only invalid if the maximum/minimum year is exceeded.
   * <p>
   * For example, 2008-12-31 minus one week would result in 2009-01-07.
   * <p>
   * This instance is immutable and unaffected by this method call.
   *
   * @param weeks the weeks to subtract, may be negative
   * @return an {@code OffsetDateTime} based on this date-time with the weeks subtracted, not null
   * @throws DateTimeException if the result exceeds the supported date range
   */
  public OffsetDateTime minusWeeks(long weeks) {
    return (weeks == Long.MIN_VALUE ? plusWeeks(Long.MAX_VALUE).plusWeeks(1) : plusWeeks(-weeks));
  }

  /**
   * Returns a copy of this {@code OffsetDateTime} with the specified number of days subtracted.
   * <p>
   * This method subtracts the specified amount from the days field decrementing the
   * month and year fields as necessary to ensure the result remains valid.
   * The result is only invalid if the maximum/minimum year is exceeded.
   * <p>
   * For example, 2008-12-31 minus one day would result in 2009-01-01.
   * <p>
   * This instance is immutable and unaffected by this method call.
   *
   * @param days the days to subtract, may be negative
   * @return an {@code OffsetDateTime} based on this date-time with the days subtracted, not null
   * @throws DateTimeException if the result exceeds the supported date range
   */
  public OffsetDateTime minusDays(long days) {
    return (days == Long.MIN_VALUE ? plusDays(Long.MAX_VALUE).plusDays(1) : plusDays(-days));
  }

  /**
   * Returns a copy of this {@code OffsetDateTime} with the specified number of hours subtracted.
   * <p>
   * This instance is immutable and unaffected by this method call.
   *
   * @param hours the hours to subtract, may be negative
   * @return an {@code OffsetDateTime} based on this date-time with the hours subtracted, not null
   * @throws DateTimeException if the result exceeds the supported date range
   */
  public OffsetDateTime minusHours(long hours) {
    return (hours == Long.MIN_VALUE ? plusHours(Long.MAX_VALUE).plusHours(1) : plusHours(-hours));
  }

  /**
   * Returns a copy of this {@code OffsetDateTime} with the specified number of minutes subtracted.
   * <p>
   * This instance is immutable and unaffected by this method call.
   *
   * @param minutes the minutes to subtract, may be negative
   * @return an {@code OffsetDateTime} based on this date-time with the minutes subtracted, not null
   * @throws DateTimeException if the result exceeds the supported date range
   */
  public OffsetDateTime minusMinutes(long minutes) {
    return (minutes == Long.MIN_VALUE ? plusMinutes(Long.MAX_VALUE).plusMinutes(1)
        : plusMinutes(-minutes));
  }

  /**
   * Returns a copy of this {@code OffsetDateTime} with the specified number of seconds subtracted.
   * <p>
   * This instance is immutable and unaffected by this method call.
   *
   * @param seconds the seconds to subtract, may be negative
   * @return an {@code OffsetDateTime} based on this date-time with the seconds subtracted, not null
   * @throws DateTimeException if the result exceeds the supported date range
   */
  public OffsetDateTime minusSeconds(long seconds) {
    return (seconds == Long.MIN_VALUE ? plusSeconds(Long.MAX_VALUE).plusSeconds(1)
        : plusSeconds(-seconds));
  }

  /**
   * Returns a copy of this {@code OffsetDateTime} with the specified number of nanoseconds
   * subtracted. <p> This instance is immutable and unaffected by this method call.
   *
   * @param nanos the nanos to subtract, may be negative
   * @return an {@code OffsetDateTime} based on this date-time with the nanoseconds subtracted, not
   * null
   * @throws DateTimeException if the result exceeds the supported date range
   */
  public OffsetDateTime minusNanos(long nanos) {
    return (nanos == Long.MIN_VALUE ? plusNanos(Long.MAX_VALUE).plusNanos(1) : plusNanos(-nanos));
  }

  //-----------------------------------------------------------------------

  /**
   * Queries this date-time using the specified query.
   * <p>
   * This queries this date-time using the specified query strategy object.
   * The {@code TemporalQuery} object defines the logic to be used to
   * obtain the result. Read the documentation of the query to understand
   * what the result of this method will be.
   * <p>
   * The result of this method is obtained by invoking the
   * {@link TemporalQuery#queryFrom(TemporalAccessor)} method on the
   * specified query passing {@code this} as the argument.
   *
   * @param <R> the type of the result
   * @param query the query to invoke, not null
   * @return the query result, null may be returned (defined by the query)
   * @throws DateTimeException if unable to query (defined by the query)
   * @throws ArithmeticException if numeric overflow occurs (defined by the query)
   */
  @SuppressWarnings("unchecked")
  @Override
  public <R> R query(TemporalQuery<R> query) {
    if (query == TemporalQueries.offset() || query == TemporalQueries.zone()) {
      return (R) getOffset();
    } else if (query == TemporalQueries.zoneId()) {
      return null;
    } else if (query == TemporalQueries.localDate()) {
      return (R) toLocalDate();
    } else if (query == TemporalQueries.localTime()) {
      return (R) toLocalTime();
    } else if (query == TemporalQueries.chronology()) {
      return (R) IsoChronology.INSTANCE;
    } else if (query == TemporalQueries.precision()) {
      return (R) NANOS;
    }
    // inline TemporalAccessor.super.query(query) as an optimization
    // non-JDK classes are not permitted to make this optimization
    return query.queryFrom(this);
  }

  /**
   * Adjusts the specified temporal object to have the same offset, date
   * and time as this object.
   * <p>
   * This returns a temporal object of the same observable type as the input
   * with the offset, date and time changed to be the same as this.
   * <p>
   * The adjustment is equivalent to using {@link Temporal#with(TemporalField, long)}
   * three times, passing {@link ChronoField#EPOCH_DAY},
   * {@link ChronoField#NANO_OF_DAY} and {@link ChronoField#OFFSET_SECONDS} as the fields.
   * <p>
   * In most cases, it is clearer to reverse the calling pattern by using
   * {@link Temporal#with(TemporalAdjuster)}:
   * <pre>
   *   // these two lines are equivalent, but the second approach is recommended
   *   temporal = thisOffsetDateTime.adjustInto(temporal);
   *   temporal = temporal.with(thisOffsetDateTime);
   * </pre>
   * <p>
   * This instance is immutable and unaffected by this method call.
   *
   * @param temporal the target object to be adjusted, not null
   * @return the adjusted object, not null
   * @throws DateTimeException if unable to make the adjustment
   * @throws ArithmeticException if numeric overflow occurs
   */
  @Override
  public Temporal adjustInto(Temporal temporal) {
    // OffsetDateTime is treated as three separate fields, not an instant
    // this produces the most consistent set of results overall
    // the offset is set after the date and time, as it is typically a small
    // tweak to the result, with ZonedDateTime frequently ignoring the offset
    return temporal
        .with(EPOCH_DAY, toLocalDate().toEpochDay())
        .with(NANO_OF_DAY, toLocalTime().toNanoOfDay())
        .with(OFFSET_SECONDS, getOffset().getTotalSeconds());
  }

  /**
   * Calculates the amount of time until another date-time in terms of the specified unit.
   * <p>
   * This calculates the amount of time between two {@code OffsetDateTime}
   * objects in terms of a single {@code TemporalUnit}.
   * The start and end points are {@code this} and the specified date-time.
   * The result will be negative if the end is before the start.
   * For example, the amount in days between two date-times can be calculated
   * using {@code startDateTime.until(endDateTime, DAYS)}.
   * <p>
   * The {@code Temporal} passed to this method is converted to a
   * {@code OffsetDateTime} using {@link #from(TemporalAccessor)}.
   * If the offset differs between the two date-times, the specified
   * end date-time is normalized to have the same offset as this date-time.
   * <p>
   * The calculation returns a whole number, representing the number of
   * complete units between the two date-times.
   * For example, the amount in months between 2012-06-15T00:00Z and 2012-08-14T23:59Z
   * will only be one month as it is one minute short of two months.
   * <p>
   * There are two equivalent ways of using this method.
   * The first is to invoke this method.
   * The second is to use {@link TemporalUnit#between(Temporal, Temporal)}:
   * <pre>
   *   // these two lines are equivalent
   *   amount = start.until(end, MONTHS);
   *   amount = MONTHS.between(start, end);
   * </pre>
   * The choice should be made based on which makes the code more readable.
   * <p>
   * The calculation is implemented in this method for {@link ChronoUnit}.
   * The units {@code NANOS}, {@code MICROS}, {@code MILLIS}, {@code SECONDS},
   * {@code MINUTES}, {@code HOURS} and {@code HALF_DAYS}, {@code DAYS},
   * {@code WEEKS}, {@code MONTHS}, {@code YEARS}, {@code DECADES},
   * {@code CENTURIES}, {@code MILLENNIA} and {@code ERAS} are supported.
   * Other {@code ChronoUnit} values will throw an exception.
   * <p>
   * If the unit is not a {@code ChronoUnit}, then the result of this method
   * is obtained by invoking {@code TemporalUnit.between(Temporal, Temporal)}
   * passing {@code this} as the first argument and the converted input temporal
   * as the second argument.
   * <p>
   * This instance is immutable and unaffected by this method call.
   *
   * @param endExclusive the end date, exclusive, which is converted to an {@code OffsetDateTime},
   * not null
   * @param unit the unit to measure the amount in, not null
   * @return the amount of time between this date-time and the end date-time
   * @throws DateTimeException if the amount cannot be calculated, or the end temporal cannot be
   * converted to an {@code OffsetDateTime}
   * @throws UnsupportedTemporalTypeException if the unit is not supported
   * @throws ArithmeticException if numeric overflow occurs
   */
  @Override
  public long until(Temporal endExclusive, TemporalUnit unit) {
    OffsetDateTime end = OffsetDateTime.from(endExclusive);
    if (unit instanceof ChronoUnit) {
      end = end.withOffsetSameInstant(offset);
      return dateTime.until(end.dateTime, unit);
    }
    return unit.between(this, end);
  }

  /**
   * Formats this date-time using the specified formatter.
   * <p>
   * This date-time will be passed to the formatter to produce a string.
   *
   * @param formatter the formatter to use, not null
   * @return the formatted date-time string, not null
   * @throws DateTimeException if an error occurs during printing
   */
  public String format(DateTimeFormatter formatter) {
    Objects.requireNonNull(formatter, "formatter");
    return formatter.format(this);
  }

  //-----------------------------------------------------------------------

  /**
   * Combines this date-time with a time-zone to create a {@code ZonedDateTime}
   * ensuring that the result has the same instant.
   * <p>
   * This returns a {@code ZonedDateTime} formed from this date-time and the specified time-zone.
   * This conversion will ignore the visible local date-time and use the underlying instant instead.
   * This avoids any problems with local time-line gaps or overlaps.
   * The result might have different values for fields such as hour, minute an even day.
   * <p>
   * To attempt to retain the values of the fields, use {@link #atZoneSimilarLocal(ZoneId)}.
   * To use the offset as the zone ID, use {@link #toZonedDateTime()}.
   *
   * @param zone the time-zone to use, not null
   * @return the zoned date-time formed from this date-time, not null
   */
  public ZonedDateTime atZoneSameInstant(ZoneId zone) {
    return ZonedDateTime.ofInstant(dateTime, offset, zone);
  }

  /**
   * Combines this date-time with a time-zone to create a {@code ZonedDateTime}
   * trying to keep the same local date and time.
   * <p>
   * This returns a {@code ZonedDateTime} formed from this date-time and the specified time-zone.
   * Where possible, the result will have the same local date-time as this object.
   * <p>
   * Time-zone rules, such as daylight savings, mean that not every time on the
   * local time-line exists. If the local date-time is in a gap or overlap according to
   * the rules then a resolver is used to determine the resultant local time and offset.
   * This method uses {@link ZonedDateTime#ofLocal(LocalDateTime, ZoneId, ZoneOffset)}
   * to retain the offset from this instance if possible.
   * <p>
   * Finer control over gaps and overlaps is available in two ways.
   * If you simply want to use the later offset at overlaps then call
   * {@link ZonedDateTime#withLaterOffsetAtOverlap()} immediately after this method.
   * <p>
   * To create a zoned date-time at the same instant irrespective of the local time-line,
   * use {@link #atZoneSameInstant(ZoneId)}.
   * To use the offset as the zone ID, use {@link #toZonedDateTime()}.
   *
   * @param zone the time-zone to use, not null
   * @return the zoned date-time formed from this date and the earliest valid time for the zone, not
   * null
   */
  public ZonedDateTime atZoneSimilarLocal(ZoneId zone) {
    return ZonedDateTime.ofLocal(dateTime, zone, offset);
  }

  //-----------------------------------------------------------------------

  /**
   * Converts this date-time to an {@code OffsetTime}.
   * <p>
   * This returns an offset time with the same local time and offset.
   *
   * @return an OffsetTime representing the time and offset, not null
   */
  public OffsetTime toOffsetTime() {
    return OffsetTime.of(dateTime.toLocalTime(), offset);
  }

  /**
   * Converts this date-time to a {@code ZonedDateTime} using the offset as the zone ID.
   * <p>
   * This creates the simplest possible {@code ZonedDateTime} using the offset
   * as the zone ID.
   * <p>
   * To control the time-zone used, see {@link #atZoneSameInstant(ZoneId)} and
   * {@link #atZoneSimilarLocal(ZoneId)}.
   *
   * @return a zoned date-time representing the same local date-time and offset, not null
   */
  public ZonedDateTime toZonedDateTime() {
    return ZonedDateTime.of(dateTime, offset);
  }

  /**
   * Converts this date-time to an {@code Instant}.
   * <p>
   * This returns an {@code Instant} representing the same point on the
   * time-line as this date-time.
   *
   * @return an {@code Instant} representing the same instant, not null
   */
  public Instant toInstant() {
    return dateTime.toInstant(offset);
  }

  /**
   * Converts this date-time to the number of seconds from the epoch of 1970-01-01T00:00:00Z.
   * <p>
   * This allows this date-time to be converted to a value of the
   * {@link ChronoField#INSTANT_SECONDS epoch-seconds} field. This is primarily
   * intended for low-level conversions rather than general application usage.
   *
   * @return the number of seconds from the epoch of 1970-01-01T00:00:00Z
   */
  public long toEpochSecond() {
    return dateTime.toEpochSecond(offset);
  }

  //-----------------------------------------------------------------------

  /**
   * Compares this date-time to another date-time.
   * <p>
   * The comparison is based on the instant then on the local date-time.
   * It is "consistent with equals", as defined by {@link Comparable}.
   * <p>
   * For example, the following is the comparator order:
   * <ol>
   * <li>{@code 2008-12-03T10:30+01:00}</li>
   * <li>{@code 2008-12-03T11:00+01:00}</li>
   * <li>{@code 2008-12-03T12:00+02:00}</li>
   * <li>{@code 2008-12-03T11:30+01:00}</li>
   * <li>{@code 2008-12-03T12:00+01:00}</li>
   * <li>{@code 2008-12-03T12:30+01:00}</li>
   * </ol>
   * Values #2 and #3 represent the same instant on the time-line.
   * When two values represent the same instant, the local date-time is compared
   * to distinguish them. This step is needed to make the ordering
   * consistent with {@code equals()}.
   *
   * @param other the other date-time to compare to, not null
   * @return the comparator value, negative if less, positive if greater
   */
  @Override
  public int compareTo(OffsetDateTime other) {
    int cmp = compareInstant(this, other);
    if (cmp == 0) {
      cmp = toLocalDateTime().compareTo(other.toLocalDateTime());
    }
    return cmp;
  }

  //-----------------------------------------------------------------------

  /**
   * Checks if the instant of this date-time is after that of the specified date-time.
   * <p>
   * This method differs from the comparison in {@link #compareTo} and {@link #equals} in that it
   * only compares the instant of the date-time. This is equivalent to using
   * {@code dateTime1.toInstant().isAfter(dateTime2.toInstant());}.
   *
   * @param other the other date-time to compare to, not null
   * @return true if this is after the instant of the specified date-time
   */
  public boolean isAfter(OffsetDateTime other) {
    long thisEpochSec = toEpochSecond();
    long otherEpochSec = other.toEpochSecond();
    return thisEpochSec > otherEpochSec ||
        (thisEpochSec == otherEpochSec && toLocalTime().getNano() > other.toLocalTime().getNano());
  }

  /**
   * Checks if the instant of this date-time is before that of the specified date-time.
   * <p>
   * This method differs from the comparison in {@link #compareTo} in that it
   * only compares the instant of the date-time. This is equivalent to using
   * {@code dateTime1.toInstant().isBefore(dateTime2.toInstant());}.
   *
   * @param other the other date-time to compare to, not null
   * @return true if this is before the instant of the specified date-time
   */
  public boolean isBefore(OffsetDateTime other) {
    long thisEpochSec = toEpochSecond();
    long otherEpochSec = other.toEpochSecond();
    return thisEpochSec < otherEpochSec ||
        (thisEpochSec == otherEpochSec && toLocalTime().getNano() < other.toLocalTime().getNano());
  }

  /**
   * Checks if the instant of this date-time is equal to that of the specified date-time.
   * <p>
   * This method differs from the comparison in {@link #compareTo} and {@link #equals}
   * in that it only compares the instant of the date-time. This is equivalent to using
   * {@code dateTime1.toInstant().equals(dateTime2.toInstant());}.
   *
   * @param other the other date-time to compare to, not null
   * @return true if the instant equals the instant of the specified date-time
   */
  public boolean isEqual(OffsetDateTime other) {
    return toEpochSecond() == other.toEpochSecond() &&
        toLocalTime().getNano() == other.toLocalTime().getNano();
  }

  //-----------------------------------------------------------------------

  /**
   * Checks if this date-time is equal to another date-time.
   * <p>
   * The comparison is based on the local date-time and the offset.
   * To compare for the same instant on the time-line, use {@link #isEqual}.
   * Only objects of type {@code OffsetDateTime} are compared, other types return false.
   *
   * @param obj the object to check, null returns false
   * @return true if this is equal to the other date-time
   */
  @Override
  public boolean equals(Object obj) {
    if (this == obj) {
      return true;
    }
    if (obj instanceof OffsetDateTime) {
      OffsetDateTime other = (OffsetDateTime) obj;
      return dateTime.equals(other.dateTime) && offset.equals(other.offset);
    }
    return false;
  }

  /**
   * A hash code for this date-time.
   *
   * @return a suitable hash code
   */
  @Override
  public int hashCode() {
    return dateTime.hashCode() ^ offset.hashCode();
  }

  //-----------------------------------------------------------------------

  /**
   * Outputs this date-time as a {@code String}, such as {@code 2007-12-03T10:15:30+01:00}.
   * <p>
   * The output will be one of the following ISO-8601 formats:
   * <ul>
   * <li>{@code uuuu-MM-dd'T'HH:mmXXXXX}</li>
   * <li>{@code uuuu-MM-dd'T'HH:mm:ssXXXXX}</li>
   * <li>{@code uuuu-MM-dd'T'HH:mm:ss.SSSXXXXX}</li>
   * <li>{@code uuuu-MM-dd'T'HH:mm:ss.SSSSSSXXXXX}</li>
   * <li>{@code uuuu-MM-dd'T'HH:mm:ss.SSSSSSSSSXXXXX}</li>
   * </ul>
   * The format used will be the shortest that outputs the full value of
   * the time where the omitted parts are implied to be zero.
   *
   * @return a string representation of this date-time, not null
   */
  @Override
  public String toString() {
    return dateTime.toString() + offset.toString();
  }

  //-----------------------------------------------------------------------

  /**
   * Writes the object using a
   * <a href="../../serialized-form.html#java.time.Ser">dedicated serialized form</a>.
   *
   * @return the instance of {@code Ser}, not null
   * @serialData <pre>
   *  out.writeByte(10);  // identifies an OffsetDateTime
   *  // the <a href="../../serialized-form.html#java.time.LocalDateTime">datetime</a> excluding the
   * one byte header
   *  // the <a href="../../serialized-form.html#java.time.ZoneOffset">offset</a> excluding the one
   * byte header
   * </pre>
   */
  private Object writeReplace() {
    return new Ser(Ser.OFFSET_DATE_TIME_TYPE, this);
  }

  /**
   * Defend against malicious streams.
   *
   * @param s the stream to read
   * @throws InvalidObjectException always
   */
  private void readObject(ObjectInputStream s) throws InvalidObjectException {
    throw new InvalidObjectException("Deserialization via serialization delegate");
  }

  void writeExternal(ObjectOutput out) throws IOException {
    dateTime.writeExternal(out);
    offset.writeExternal(out);
  }

  static OffsetDateTime readExternal(ObjectInput in) throws IOException, ClassNotFoundException {
    LocalDateTime dateTime = LocalDateTime.readExternal(in);
    ZoneOffset offset = ZoneOffset.readExternal(in);
    return OffsetDateTime.of(dateTime, offset);
  }

}
